Compressors may be used in a wide variety of industrial and residential applications to circulate refrigerant to provide a desired heating or cooling effect. For example, a compressor may be used to provide heating and/or cooling in a refrigeration system, a heat pump system, a heating, ventilation, and air conditioning (HVAC) system, or a chiller system. These types of systems can be fixed, such as at a building or residence, or can be mobile, such as in a vehicle. Vehicles include land based vehicles (e.g., trucks, cars, trains, etc.), water based vehicles (e.g., boats), air based vehicles (e.g., airplanes), and vehicles that operate over a combination of more than one of land, water, and air.
Small to mid-sized refrigerated truck systems can include one or more eutectic plates. The eutectic plates are disposed within a box of the corresponding truck and are used to maintain an air temperature within the box and thus contents of the box below a predetermined temperature. The eutectic plates are filled with a fluid and are designed to freeze at a certain temperature. The eutectic plates can be cooled to a medium temperature (e.g., 35° F.) or a low temperature (e.g., less than or equal to 0° F.). The refrigerated truck systems typically pull down a temperature of the eutectic plates at night while the truck is parked at a depot. The refrigerated truck systems typically do not run while the truck is in service (i.e. while standing at a site or while traveling between sites). The refrigerated truck systems do not maintain box set point temperatures accurately and therefore are typically used for transporting frozen goods, not fresh goods which require tighter temperature maintenance and set point tolerances.
Some refrigerated truck systems include, in addition to the eutectic plates, a blower/evaporator (hereinafter referred to as a “blower evaporator”). The blower evaporator is run as needed and to maintain a temperature within a box of the truck while the corresponding truck is in route between sites. Eutectic plate evaporators contain long refrigerant lines which provide large volume and surface area for oil logging to occur. When switching from the eutectic plate evaporator to the blower evaporator, the eutectic plates are closed off from the rest of the system. If the eutectic plates are closed off from the rest of the system when running the blower evaporator, any oil in the plates is trapped. Oil logging in the plates may cause reduction in compressor oil level which could potentially cause a failure.
The background description provided here is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.